Somebody explain motor kv please

[trillian]

As it goes I'm inclined to agree from simple logic.. but do you know at what point upping the KV and reducing pinion teeth reduces effciiency? And that is a genuine question as a 9t pinion should still be quite sane...700kv?

I think there are electrical reasons for certain KVs at a given voltage. I don't pretend to know the details as it starts to get into factors of hysteresis, magnetic flux density, iron losses etc.

[Mike Sanders]

It must also be borne in mind that a small pinion is generally less efficient than a larger one because the angle at which the teeth engage is greater.

[trillian]

It must also be borne in mind that a small pinion is generally less efficient than a larger one because the angle at which the teeth engage is greater.

Yeah, plus you have less surface area engaging so I have generally gone for bigger pinions whenever possible.

[waveydavey]

As it goes I'm inclined to agree from simple logic.. but do you know at what point upping the KV and reducing pinion teeth reduces effciiency? And that is a genuine question as a 9t pinion should still be quite sane...700kv?

Probably, let me sleep the Stella before I miss spell the answer

[pgkevet]

This is worth a read: Which chinese factories make various brushless motor brands? - Page 3
Now I recognise that list doesn't have 700 size motors in it but does get to 50 size.
When you look at the components of a brushless motor - which is essentially quite simple - I wonder where the differences are and where the brand-name fanboy bullsite starts and finishes. I'd be hard to convice that materials quality is much difefrent except perhaps with the bearings and the wind type and for most large diameter wire windings I'd guess they probably get hand wound anyway (if you think about the need to set up each sector for a few small turns). the diference is more likely to be in the wind type and quality control of the finish windings. I'd speculate that many companies claiming to make their own buy the components in rather than cuttng them themselves and just wind and assemble.

Whch still leaves two basic questions - the ideal design for electromechanical efficiency in the motors themselves for a 700 and the ideal choice of motor and pinion for the power-train efficiency.

You can also bet your shirt that the esc has a lot more to do with things when efficiency is involved.

A shame there isn't a list of independantly tested motors and independantly tested escs to bypass the usual fanboy assumptions.

Laser etching, smart colour schemes, a tin with a logo, a demo by someone who could 3D a brick, price tag - it's all meaningless compared to runnimg test comparing output torque, current draw, temperature and shock resistance and start/stop load:time using each esc on each motor.

[Ross Northcott]

well at least you know your Align motor wasn't made by some Chinese factory, Align motors are made in Europe, Holland to be exact, as are most of Aligns conponants, its does make sense really as they have the biggest stockpile amount of CHEESE and lots a varities to cope with demand.

[pgkevet]

Your confusing align with windmill helis and thier indica700, sativa650, gouda 500 and leerdammer 450 all fitted with diamond motors, tulipwood blades and rottendamn bolts

[trillian]

Your confusing align with windmill helis and thier indica700, sativa650, gouda 500 and leerdammer 450 all fitted with diamond motors, tulipwood blades and rottendamn bolts

And their own version of the DFC head (dairy fat control).